The use of a reusable biopsy gun and a biopsy needle comprises a number of steps.
In a first step, the biopsy needle is loaded into the biopsy gun.
In a second step the biopsy gun is armed, this is typically done by compressing two springs, one for the cannula of the biopsy needle and one for the stylet of the biopsy needle.
In a third step the biopsy needle is inserted into the sampling site, e.g. soft tissue for example from the prostate, from which samples are desired.
Finally, in a fourth step, the biopsy gun is fired, e.g. when the gun has been armed by springs these are released. This will result in the stylet being fired first. The stylet is provided with a small recess at the tip into which sample tissue will move. Secondly, the cannula is fired which cuts off the sample tissue and contains it in the recess. The biopsy needle is then pulled out of the body and the sample tissue may be retrieved.
The steps may vary a little, and other steps may be introduced in between, however, most procedures generally follow the above.
The present invention relates primarily to the first step. Loading of the biopsy needle into the biopsy gun comprises a number of handling issues. In particular because the nurse or surgeon has to handle two separate elements, one of which is very sharp and thus may involve unintentionally puncturing of the protective barrier, such as gloves, and even the tissue of the person loading the needle into the gun.
In a number of known biopsy needles, the cannula and stylet are freely slidable relative to each other when loading the biopsy needle into the biopsy gun. This results in a high risk of the person handling the gun being pierced when loading the gun.
In order to overcome this, some biopsy needles have been formed with locking members in order to prevent unintentional sliding movement between the cannula and the stylet. However, these comprise a third element which has to be removed before or after loading of the needle. Furthermore, during manufacture such a third element adds to the cost of the biopsy needle.
Moreover, using such needles with known biopsy guns poses another problem in that the known biopsy guns are not adapted to handle such an additional element. Thus, the locking element has to be removed prior to loading, thereby removing the advantage of having a locked relationship between cannula and stylet during this step.
Thus, there is both a need for providing a biopsy needle that solves the issues addressed above and a biopsy gun suitable for use with such a biopsy needle.